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This includes the activation synthesis theory—the theory that dreams result from brain stem activation during REM sleep; the continual activation theory—the theory that dreaming is a result of activation and synthesis but dreams and REM sleep are controlled by different structures in the brain; and dreams as excitations of long-term memory ...
Rapid eye movement sleep (REM sleep or REMS) is a unique phase of sleep in mammals (including humans) and birds, characterized by random rapid movement of the eyes, accompanied by low muscle tone throughout the body, and the propensity of the sleeper to dream vividly. The core body and brain temperatures increase during REM sleep and skin ...
REM sleep may be a more evolutionarily recent sleep state, and is prominent in most birds and mammals, although may exist in reptiles and other vertebrates to varying degrees. [3] REM stands for rapid eye movement. It is generally a later sleep state following non-REM (NREM) sleep. [3] It is regulated in part by the pontine brainstem.
The basic rest–activity cycle (BRAC) is a physiological arousal mechanism in humans proposed by Nathaniel Kleitman, [1] hypothesized to occur during both sleep and wakefulness. Empirically, it is an ultradian rhythm of approximately 90 minutes (80–120 minutes [ 2 ] ) characterized by different levels of excitement and rest.
This is when most dreaming occurs. Overall, REM sleep usually accounts for up to two hours of sleep time and most people can remember their dreams only if woken directly from REM sleep. [3] It is known from laboratory studies of brain waves that, just before entering REM sleep and while in it, powerful electrical signals pass through the brain.
REM sleep, also known as paradoxical sleep, represents a smaller portion of total sleep time. It is the main occasion for dreams (or nightmares), and is associated with desynchronized and fast brain waves, eye movements, loss of muscle tone, [20] and suspension of homeostasis. [21] The sleep cycle of alternate NREM and REM sleep takes an ...
During a normal night of sleep, a person will alternate between periods of NREM and REM sleep. Each cycle is approximately 90 minutes long, containing a 20-30 minute bout of REM sleep. [7] NREM sleep consists of sleep stages 1–4, and is where movement can be observed. A person can still move their body when they are in NREM sleep.
REM sleep is decreased during the first half of the sleep period and stage 1 sleep is increased in the second half of the sleep period. [5] Most antidepressants, in particular selective serotonin re-uptake inhibitors (SSRIs), such as citalopram and paroxetine, are potent inhibitors of REM sleep and may also cause a REM rebound on discontinuation.